Patch series "mm: fix the names of general cma and hugetlb cma", v2.
The current code of CMA can only work when users pass a const string as
name parameter. we need to fix the way to handle names in CMA. On the
other hand, to avoid name conflicts after enabling CMA_DEBUGFS, each
hugetlb should get a different CMA name.
This patch (of 2):
If users give a name saved in stack, the current code will generate magic
pointer. if users don't give a name(NULL), kasprintf() will always return
NULL as we are at the early stage. that means cma_init_reserved_mem()
will return -ENOMEM if users set name parameter as NULL.
[natechancellor@gmail.com: return cma->name directly in cma_get_name]
Link: https://github.com/ClangBuiltLinux/linux/issues/1063
Link: http://lkml.kernel.org/r/20200623015840.621964-1-natechancellor@gmail.com
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/20200616223131.33828-2-song.bao.hua@hisilicon.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
const char *cma_get_name(const struct cma *cma)
{
- return cma->name ? cma->name : "(undefined)";
+ return cma->name;
}
static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
* subsystems (like slab allocator) are available.
*/
cma = &cma_areas[cma_area_count];
- if (name) {
- cma->name = name;
- } else {
- cma->name = kasprintf(GFP_KERNEL, "cma%d\n", cma_area_count);
- if (!cma->name)
- return -ENOMEM;
- }
+
+ if (name)
+ snprintf(cma->name, CMA_MAX_NAME, name);
+ else
+ snprintf(cma->name, CMA_MAX_NAME, "cma%d\n", cma_area_count);
+
cma->base_pfn = PFN_DOWN(base);
cma->count = size >> PAGE_SHIFT;
cma->order_per_bit = order_per_bit;
#include <linux/debugfs.h>
+#define CMA_MAX_NAME 64
+
struct cma {
unsigned long base_pfn;
unsigned long count;
spinlock_t mem_head_lock;
struct debugfs_u32_array dfs_bitmap;
#endif
- const char *name;
+ char name[CMA_MAX_NAME];
};
extern struct cma cma_areas[MAX_CMA_AREAS];